The Study On Techniques Of DC Circuit Breaker For Magnet Power Supply System In Fusion Facility

DC circuit breaker as the key components of fusion facility magnet power supply system, is applied to establish the plasma current and protect magnet coils. ITER and future fusion facility power supply system need DC circuit breaker with high parameters such as voltage, current and life urgently. The reference scheme of ITER is still in development, however, China didn’t participate in the development work. Taking into account the need of the DC circuit breaker used in future fusion facility in China, based on the digestion and absorption of the reference scheme of ITER, the study on DC circuit breaker technologies of fusion facility power supply system is carried out, providing a reference to the development of DC circuit breaker used in future fusion facility in China.The key technology adopted by the reference scheme of DC circuit breaker used in ITER is digested and absorbed, a DC circuit breaker of fusion facility magnet power system is designed, the ability to withstand voltage of the DC circuit breaker is improved by the series SCRs, the current-carrying capacity of the mechanical switch is enhanced by the design of the main contact of the switch, the arcing time and arc voltage is reduced by the design of the installation and connection of the DC circuit breaker;the SCRs’ current-carrying capacity is calculated, the SCRs’ turn-off reliability is improved by de design of artificial-zero-current network, the voltage balance among the SCRs is ensured by the parallel resistance. the key process of the design is analyzed by Simulink, the feasibility of the design is verified.In view of the mechanical switch’s demand for high-speed operation mechanism, the electromagnetic repulsion mechanism is put forward, the structure parameters of the electromagnetic repulsion mechanism is designed, the feasibility is verified by simulation based on the ANSOFT model, the structure parameters’ influence to the mechanism’s output characteristics is analyzed, in view of the mechanism’s demand for high-performance buffer, the hydraulic buffer is put forward to electromagnetic repulsion mechanism.The design of the DC circuit breaker applied in fusion facility, which meet the technical requirements, rather has economical efficiency, has some reference significance to fusion facility that is going to be built in China.